Frontend doesn't always mean using JS. You can use a well-designed, modern language like ClojureScript instead that isn't anything like using JS, yet nevertheless has the same access to the browser.
Well... there are only two standard APIs for the front end: DOM and the web API (browser stuff and HTML5 things). Once comfort with those is achieved you suddenly need so much less code to do radically more ambitious things.
The time saved in both authoring and maintenance pays for itself in learning the standards.
The time saved in both authoring and maintenance pays for itself in learning the standards.